Mechanical behavior and durability of fibre reinforced mortar in an aggressive environment

International audience; This study was carried out to examine the mechanical behavior and durability of mortar with or without addition of silica fume, with and without steel fibre reinforcement. Three tests were carried out: strength, depth of pH reduction and micro-structural analysis by SEM. The mixes studied had two water cement ratios (0.5; 0.65); with a 0.5% steel fibre content and 10% silica fume content (in substitution of cement). To characterize the durability performance of the mortars studied, samples were exposed to one-year in three environments: wet environment (control samples under laboratory conditions, 20°C and 95% RH) and exposure samples: in cyclic environment (wetting and drying) and a sewage pumping station sump (an aggressive environment). SEM observations were carried out on samples to study the micro structural changes in the mortar's matrix. One sees the organic matter deposits located inside a pore and one can see the formation of the secondary ettringite. It is concluded that the compressive strength of the samples are relatively unaffected by mix type and environment. The samples exposed to sewage exhibited evidence a depth of pH reduction.